Implement Function.prototype.toMethod.

test/mjsunit/harmony/toMethod.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+//
+// Flags: --harmony-classes --allow-natives-syntax
+
+
+(function TestSingleClass() {
+  function f(x) {
+    var a = [0, 1, 2]
+    return a[x];
+  }
+
+  function ClassD() { }
+
+  assertEquals(1, f(1));
+  var g = f.toMethod(ClassD.prototype);
+  assertEquals(1, g(1));
+  assertEquals(undefined, f[%HomeObjectSymbol()]);
+  assertEquals(ClassD.prototype, g[%HomeObjectSymbol()]);
+}());
+
+
+(function TestClassHierarchy() {
+  function f(x) {
+    return function g(y)  { x++; return x + y; };
+  }
+
+  function Base() {}
+  function Derived() { }
+  Derived.prototype = Object.create(Base.prototype);
+
+  var q = f(0);
+  assertEquals(2, q(1));
+  assertEquals(3, q(1));
+  var g = q.toMethod(Derived.prototype);
+  assertFalse(g === q);
+  assertEquals(4, g(1));
+  assertEquals(5, q(1));
+}());
+
+
+(function TestErrorCases() {
+  var sFun = Function.prototype.toMethod;
+  assertThrows(function() { sFun.call({}); }, TypeError);
+  assertThrows(function() { sFun.call({}, {}); }, TypeError);
+  function f(){};
+  assertThrows(function() { f.toMethod(1); }, TypeError);
+}());
+
+
+(function TestPrototypeChain() {
+  var o = {};
+  var o1 = {};
+  function f() { }
+
+  function g() { }
+
+  var fMeth = f.toMethod(o);
+  assertEquals(o, fMeth[%HomeObjectSymbol()]);
+  g.__proto__ = fMeth;
+  assertEquals(undefined, g[%HomeObjectSymbol()]);
+  var gMeth = g.toMethod(o1);
+  assertEquals(fMeth, gMeth.__proto__);
+  assertEquals(o, fMeth[%HomeObjectSymbol()]);
+  assertEquals(o1, gMeth[%HomeObjectSymbol()]);
+}());
+
+
+(function TestBoundFunction() {
+  var o = {};
+  var p = {};
+
+
+  function f(x, y, z, w) {
+    assertEquals(o, this);
+    assertEquals(1, x);
+    assertEquals(2, y);
+    assertEquals(3, z);
+    assertEquals(4, w);
+    return x+y+z+w;
+  }
+
+  var fBound = f.bind(o, 1, 2, 3);
+  var fMeth = fBound.toMethod(p);
+  assertEquals(10, fMeth(4));
+  assertEquals(10, fMeth.call(p, 4));
+  var fBound1 = fBound.bind(o, 4);
+  assertEquals(10, fBound1());
+  var fMethBound = fMeth.bind(o, 4);
+  assertEquals(10, fMethBound());
+}());
+
+(function TestOptimized() {
+  function f(o) {
+    return o.x;
+  }
+  var o = {x : 15};
+  assertEquals(15, f(o));
+  assertEquals(15, f(o));
+  %OptimizeFunctionOnNextCall(f);
+  assertEquals(15, f(o));
+  var g = f.toMethod({});
+  var o1 = {y : 1024, x : "abc"};
+  assertEquals("abc", f(o1));
+  assertEquals("abc", g(o1));
+} ());
+
+(function TestExtensibility() {
+  function f() {}
+  Object.preventExtensions(f);
+  assertFalse(Object.isExtensible(f));
+  var m = f.toMethod({});
+  assertTrue(Object.isExtensible(m));
+}());